Millions of flights take off and land in China every year, almost all of them using planes made by Boeing and Airbus, the world’s two leading aircraft manufacturers. For years, China has been working to change that and, this week, it celebrated a milestone in that quest: the first commercial flight of a large passenger jet made in China. The C919 jet, made by Comac, a Chinese state-run aerospace manufacturer, flew about 130 passengers from Shanghai to Beijing for China Eastern Airlines on Sunday, according to Chinese state media. It…